Degradabilidade Ruminal in Situ da Matéria Seca e Proteína Bruta das Silagens de Milho e Sorgo e de Alguns Alimentos Concentrados

Abstract

The ruminal dry matter (DM) and crude protein (CP) degradability of some feeds were evaluated by the in situ technique, using three Holstein cows. The concentrate feeds were ground through a 2 mm screen and the forage and the cassava root, in 5 mm screen, and incubated in nylon bag (53μ). The effective degradability (ED) of DM (5%/h) for corn silage, sorghum silage, corn, sorghum, wheat bran, triticale, cassava scraping, citrus pulp, soybean meal, cottonseed meal and meat and bone meal was: 54.8, 46.0, 37.6, 54.3, 80.4, 88.7, 75.0, 67.5, 74.1, 65.9, and 39.4%, respectively. The effective degradabilities CP were: 70.4, 67.9, 40.2, 42.7, 86.5, 89.3, 71.7, 62.1, 57.3, 81.4, and 47.5%, respectively. The feed group was made according to ruminal DM and CP degradation dynamics, by means of Tocher method. The potentially degradable fraction and its degradation rate were the variables of the highest discrimination power for the group formation.